A typical headset combines a microphone with headphone speakers for both ears. The microphone is typically encased in a tubular structure proximal to a user's mouth to receive the user's speech signal. When the speech signal travels from the user's mouth through the air into the microphone, the signal quality may be degraded by ambient noise as the microphone is exposed to the external environment.
Some advanced headsets incorporate a microphone as part of an earpiece that covers or fits into a person's ear. The earpiece forms a seal that blocks the ambient noise from entering the ear and allows the microphone to pick up a user's speech directly from the user's ear structure. The resulting microphone signal has improved signal to noise ratio (SNR) due to less noise disturbance, but in some situations the ambient noise may leak through the earpiece into the ear, and, due to frequency distortion in the speech signal propagation path, the speech may sound muffled or even unintelligible.
Thus, there is a need for improving the sound quality of microphone signals transmitted by an in-ear microphone.